Air Separation - Simply put, it is a set of industrial equipment used to separate various gas components in the air to produce oxygen, nitrogen and argon. There are also rare gases such as helium, neon, argon, krypton, xenon, radon, etc.

A. Air separation can be divided into.

1. Air filtration system; dust filtration to remove dust and mechanical impurities

2. Air compressor system; works on gas, improves energy, and has cooling capacity

3. Air pre-cooling system; pre-cools the gas to reduce energy consumption and improve economy. The pre-cooling one-time throttling cycle is more economical than the non-precooling one-time throttling cycle. It increases the refrigeration cycle, reduces the workload of the heat exchanger, and fully utilizes the refrigeration capacity of the product;

4. Air purification system; explosion-proof and purified; air is composed of multiple components. In addition to gas components such as oxygen and nitrogen, there are also merged impurities such as water vapor, carbon dioxide, acetylene and a small amount of dust. These impurities will cause greater harm as the air enters the air compressor and air separation equipment. Solid impurities will wear out the operating parts of the air compressor, block the cooler, and reduce the cooling effect; water vapor and carbon dioxide will condense during the air cooling process. Ice precipitation will block equipment and gas pipelines, causing the air separation equipment to be unable to produce. Acetylene entering the air separation equipment will cause explosion accidents, so in order to ensure the safe operation of the oxygen generator, it is very necessary to remove these impurities.

Utilizes the difference in adsorption capacity of solid adsorbents for multi-component mixed gases; the production ratio of oxygen and nitrogen is 1: (2.5~3.5); function: adsorbs water, carbon dioxide, acetylene, propylene, propane, heavy hydrocarbons in the air compounds, N2O and other impurities.

5. Air compression and expansion system; refrigeration system and heat exchange system. During the expansion process, there is external power output. The potential energy of the expanded gas increases, which requires energy consumption. This energy needs to be compensated with kinetic energy, so the gas temperature must decrease. Heat exchange system: realizes energy transfer, improves economy, and achieves low-temperature operating conditions;

6. Air separation system; nitrogen/oxygen separation mainly consists of a distillation tower system. After air separation, an appropriate amount of expanded air (20% to 25% of air) can be directly sent to the upper tower for rectification; from the top of the lower tower or condensation Nitrogen is extracted under the top cover of the evaporator, reheated, and then enters the nitrogen turboexpander. The expander returns it through its cooling capacity, and is then output or emptied as a product.

7. Oxygen compression; 8. Nitrogen compression; 9. Liquid storage vaporization system.

Brief description of process

After dust and mechanical impurities are removed in the air inlet filter, the raw air enters the air turbine compressor, is compressed to about 0.62MPa (A) with the help of the intercooler for intercooling, and then enters the air cooling tower for cooling.

By performing heat and mass exchange with water in a direct contact air cooling tower, the air is cooled to ~10°C and then enters the alternating molecular sieve adsorber. There are two parts of water used to cool the air: one part is normal temperature water, which is pressurized by a water pump and enters the middle of the air cooling tower; the other part is called chilled water, which is cooled by ordinary cooling water through a water nitrogen tower, and then pressurized by a cryogenic water pump and enters the air cooling tower. Tower top.

The air from the air cooling tower enters the molecular sieve adsorber, which is a vertical double adsorption tower layer used to remove water, carbon dioxide and some hydrocarbons from the air to obtain clean and dry air. Two adsorbers are used alternately, that is, one adsorber absorbs impurities and the other adsorber is regenerated with dirty nitrogen.